Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C1/00—Reactor types
  • G21C1/04—Thermal reactors ; Epithermal reactors
  • G21C1/06—Heterogeneous reactors, i.e. in which fuel and moderator are separated
  • G21C1/07—Pebble-bed reactors; Reactors with granular fuel
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C9/00—Emergency protection arrangements structurally associated with the reactor, e.g. safety valves provided with pressure equalisation devices
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/30—Nuclear fission reactors

Definitions

• the invention relates to a high temperature reactor with a core of preferably spherical fuel elements, more particularly to a reactor with an upward helium coolant flow through a core and with a graphite roof reflector, a side reflector, and bottom reflector, and forming a cylindrical cavity to receive the core.
• DE-OS 32 45 022 (corresponding to U.S. Pat. No. 4,675,155) and 33 45 113 (corresponding to U.S. Pat. No. 4,664,871) and DE P 32 12 266, the disclosures of which are expressly incorporated by reference herein, show reactor installations with graphite reflectors.
• iodine compounds in particular iodides, are excessively volatile in the temperature range of 1000 to 1200 degrees C. This temperature range corresponds to the accident temperature of the roof reflector. It must also be taken into account that most iodine compounds in the temperature range are already displaying decomposition phenomena, which do not permit the obtention of the low partial pressure desired for the absorption of iodine.
• this object is attained by utilization of a roof reflector in the upper part of which exhibits metal atoms or molecules suitable for bonding volatile iodine and cesium iodide or molecules of compounds of these metals, built individually, dissolved in a high dilution in the cracked binder material of the graphite.
• the high temperature reactor according to the invention is thus characterized by a greatly improved and inherent retention effect for iodine and cesium iodide, combined with the advantage that a reduction of environmental contaminations may be obtained without the installation of additional filters for the case of accidents.
• Alkaline earth metals and/or metals of the rare earths are suitable as the metal atoms for the proposed incorporation.
• oxides and carbides of barium and/or lanthanum may be used.
• the aforementioned substances must be present in a dilution of 1:100 to 1:10,000 in the cracked binder material; they are dissolved in said binder material. The high dilution is required so that the atoms of molecules incorporated would be present individually and are able to bind free iodine. Under these conditions, the iodine is not only bound chemically to the doping atoms or molecules, but the iodide formed in this manner is also retained additionally in the matrix of the cracked binder material.
• the initial materials for the incorporation may include alcoholates or metallic salts of the metals involved.
• Ba (C 3 H 5 )2 or La (C 2 H 5 ) 3 are added to the liquid binder material.
• the doping atoms are present in the form of individual, finely distributed oxides.
• Metal salts of the cyclop stages for example Ba (C 5 H 5 ) 2 and La (C 5 H 5 ) 3 , may be used if introduction of doping atoms in the form of carbides in the binder material is desired (second case).
• the mixture is cracked in the usual manner in the temperature range between 1500 degrees and 1800 degrees C. after the substances are mixed with the liquid binder material.
• the nuclei of the doping atoms may accumulate on the surfaces of the crystalline grains of the cracked binder material.
• the conversion of gaseous iodide would lead, although to a small extent only, by these doping atoms to the formation of iodides not structurally bound, thereby reducing the retention of the iodine, as the iodide formed would be partially volatile at the temperatures given.
• molecules of the oxides of silicon, zirconium or titanium or other high temperature resistant oxides may be incorporated into the cracked binder material of the graphite in an advantageous further embodiment.
• the mixing ratio of these additional substances with the initiallY cited metals is within a range of 1:1 to 5:1.
• the cracked binder material is partially gasified, in addition to the doping metal atoms or molecules, those of the additionally incorporated molecules are also released, for example silicon oxide molecules. These substances form compounds with each other, for example silicates, which practically cannot be attacked by iodine. This prevents the volatilization of the iodine by way of an iodide. If zirconium and titanium oxides are used, the doping atoms are molecules released form additional zirconate and titanate substances.
• silicones may be used as the initial material for the additional substances.
• oxides of titanium or zirconium appropriately alcoholates of these metals are used as the initial materials.
• the silicones and/or alcoholates are added together with the initial materials for the doping atoms or molecules to the liquid binder material and the mixture cracked as described above, in the manner usual in the production of graphite.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Carbon And Carbon Compounds (AREA)
• Compositions Of Oxide Ceramics (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6347434

Family Applications (1)

Country Status (2)

Citations (10)

• 1988
  • 1988-02-15 DE DE3804643A patent/DE3804643A1/de active Granted
• 1989
  • 1989-02-14 US US07/310,663 patent/US5011653A/en not_active Expired - Fee Related

Patent Citations (12)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events